Show level of mobs

[Josito]

Sometime I played in a server C1 in which the mobs show their level. I mean, when you select a mob it shows its name and its level like <Elpy lvl. 1>

How can I do this ?

Thanks

[MentaL]

[Bretonnian]

need edit the client

[Josito]

Got IT!!! I have the solution but still cannot post URL cause I&#180;ve less than 5 posts